pollex
Concise Oxford English Dictionary © 2008 Oxford University Press:
pollex /ˈpɒlɛks/
▶noun (pl. pollices /-lɪsiːz/) Anatomy & Zoology the innermost digit of a forelimb, especially the thumb in primates.
– origin C19: from L., lit. ‘thumb or big toe’.
'pollex' also found in these Oxford entries:

